Terahertz virus-sized gold nanogap sensor

Abstract We demonstrated an ultra-sensitive terahertz virus detection method combined with virus-sized gold nanogaps filled Al 2 O 3 . Large-area high-density 20 nm-gap rectangular loop structures, containing a resonant frequency in the range, were fabricated on 4-inch wafer using atomic layer lithography. When target viruses 60 nm diameter located nanogaps, we observed significant redshift of peak already average number about 100 per unit due to strong field confinement and enhancement near gap. Furthermore, when was tightly attached etched gap like bridge connecting metals, its sensitivity is doubled compared unetched gap, which resulted 400% more resonance shift single particle than our previous work. Full-wave simulations theoretical calculations based modal expansions good agreement experiments, revealing that transmission spectrum mostly determined by change refractive index two-dimensional-like optical hotspot nanogap. A further step could be taken increase tuning nanogap-loops absorption frequencies associated intermolecular vibrational modes fingerprinting them as well.